The invention relates, in general, to a stapling device for sheet stacks and, more particularly, to a stapling device in which the thickness of the stack to be stapled is secured by a movable sensing element cooperating with such stack, the movement of the sensing element depending on its path length determined by the thickness of the stack and serving to control actuation of a stapling head of the device.
Stapling devices for use in automated apparatus typically include at least one stapling head, a drive means for the stapling head, a switching means actuating the drive means of the stapling head to perform the stapling operation. Further, such stapling devices may include a sensor which cooperates with the switching means such that the stapling operation is blocked when a sheet stack of an inadmissible thickness is present (see for example U.S. Pat. No. 3,317,026). Such sensor, and its cooperation to control the stapling operation, are of complex construction.